Guidance devices are well known in the art for use with X-ray or scanning devices providing a surgeon with multi-dimensional viewing of the skeletal and supporting structure wherein various medical procedures on the body can be performed. Such devices provide a stability to a surgical instrument not possible by human hands and in many instances allow hands free operation. Typically the guidance device is set upon a structure used in combination with a scan table. The structure can be moved yet maintain a level position despite vertical or horizontal disposition. Bracketry is available to support items such as a needle. A protractor may be used to determine the desired plane, the rotation of which is set to match angulation of a target path as determined by a scan.
The CT scan allows the determination of the ultimate target path so as to avoid penetration of vital structures such as nerves or vessels thereby minimizing both the time of surgery and the extent thereof. Common to prior art devices is their targeting limitations.
Prior art discloses a number of stereotactic devices which are dependent upon the diagnostic mapping of a patient such as those generated by a multi-plane scanner for use in locating an internal region of interest in advance of a clinical procedure.
Variations of stereotactic devices include a means for rotating a probe holder in a vertical or horizontal plane using protractors to verify finite movement in length or angle. The aiming of the probe is accomplished by use of a CT scan providing coordinates of a presumed target within the body. A scan can be made and the aim of the medical device verified by superimposing the target on a scanner printout. When a guide is accurately aimed both in the coronal and sagittal planes, a medical instrument can be inserted into the body at the proper depth, the position verified by a CT scan or roentgenogram.
Stereotactic devices are unique in that they are adaptable to align and orientate a variety of medical instruments such as guide wires, needles, and cannulas into the human body so as to perform such procedures as percutaneous dissectomies, cysts, aspirations, tumor localizations, biopsies and the like type operations.
U.S. Pat. No. 4,791,934 discloses a clinical method in positioning a surgical instrument by first imaging a patient so as to produce a three-dimensional diagnostic mapping data, transferring the patient to a treatment station by generating a dimensional calibration reference image through the patient followed by configuring an analogous two-dimensional image from the three-dimensional diagnostic mapping data. The calibration reference and diagnostic data of the images are then determined to place the relative orientation between the patient and the three-dimensional mapping data so as to orient the surgical instrument in a precise position relative to the patient for treatment of the structure.
U.S. Pat. No. 5,308,352 discloses a stereotactic device which is adapted for use with a scanner when a patient is placed upon the surface of a CT scan table. The device consists of a carrier for a medical device which is placed on a horizontal bridge supported by two vertical legs that are slidably adjustable along the horizontal length of the scan table with a means for locking thereto. The limitation to the instant invention is most notable on the rotation of the carrier mechanism relative to the vertical legs. The radial rotation of the medical device is limited in its holding of the device that would be inserted into the body due to the fixed position of the vertical legs. With such technology the surgeon can accurately place biopsy needles in drainage catheters within a body carefully avoiding critical areas such as nerves, veins, and muscle that may adversely affect the patient.
U.S. Pat. No. 5,047,036 discloses a stereotactic guidance device consisting of a stainless steel bridge which spans a scanner table and is either mounted directly to the table or mounted on two anchored vertical side rails permanently mounted to the floor.
Thus, what is needed in the art is a portable, true stereotactic guiding mechanism for medical devices may work in conjunction with an X-ray or CT scanner so as to accurately position a surgical instrument in a three-dimensional plane so as to allow a surgical operation on a patient with minimal setup time or exploratory disruption to the body.